Many electronic devices on the market today often use power converters to convert electric energy from one form to another (e.g., converting between alternating current and direct current), amplifying a voltage or current of an electrical signal, modifying a frequency of an electrical signal, or some combination of the above. Examples of power converters may include boost converters, buck converters, and audio amplifiers (including, but not limited to Class D and Class H amplifiers). Such power converters often employ a switched output stage, an example of which is shown in FIG. 1. In FIG. 1, switched output stage 100 comprises a pull-up device 102 (e.g., a switch, a p-type metal-oxide-semiconductor field effect transistor, etc.) coupled at its non-gate terminals between a supply voltage and an output node and a pull-down device 104 (e.g., a switch, an n-type metal-oxide-semiconductor field effect transistor, etc.) coupled at its non-gate terminals between a ground voltage and the output node. Predriver circuitry 106 may receive an input voltage vIN (typically a pulse-width-modulated input voltage signal) and apply control logic and/or buffering to such input voltage to drive a pull-up driver device driving signal voltage vP to the gate terminal of pull-up device 102 and to drive a pull-down driver device driving signal voltage vN to the gate terminal of pull-down device 104, wherein vP and vN are each a function of vIN. Accordingly, switched output stage 100 generates an output voltage vOUT to its output node which is a function of vIN.
To generate the output voltage vOUT, pull-up device 102 and pull-down device 104 will alternately turn on based on vP and vN. In addition, load current delivered by switched output stage to a load coupled to the output node. Such load may apply a low-pass filter to the output voltage vOUT such that the load current is phase-shifted from output voltage vOUT which may have one of two directions—flowing “out” from switched output stage 100 to the load or flowing “in” from the load to switched output stage 100—wherein such direction of an instantaneous current may not be readily known. If current is flowing from the load to the output node, the drive voltage vN of pull-down device 104 effectively controls voltage and current transition of the output node, while if current is flowing from the output node to the load, the drive voltage vP of pull-up device 102 effectively controls voltage and current transition of the output node. Thus, if current direction can be effectively determined, such information might be used to control output node transitions.